1. Field of the Invention
The present invention relates to a method for manufacturing a recording head which is used for performing recording by using a liquid such as ink.
2. Description of the Related Art
Conventionally, a method for manufacturing a recording head is disclosed in Japanese Patent Application Laid-Open No. H04-216951, which includes forming a flow channel and an ejection orifice by setting a sensitivity ratio in photoresists to be stacked, stacking the photoresists so as not to deform a flow channel of a lower layer, which flow channel has been optically determined, exposing the upper layer to light, and collectively developing the lower layer and the upper layer. In addition, a method for manufacturing the recording head is disclosed in Japanese Patent No. 4195347, which includes forming a flow channel and an ejection orifice by providing an exposure stoppage layer which is formed of a photoresist that intercepts ultraviolet light, between an upper layer and a lower layer, stacking the photoresist so as not to deform a flow channel of the lower layer, which flow channel has been optically determined, exposing the upper layer to light, and developing the lower layer and the upper layer.
However, in the methods for manufacturing a recording head described in Japanese Patent Application Laid-Open No. H04-216951 and Japanese Patent No. 4195347, the photoresist containing a polymerization initiator which initiates the polymerization of the lower layer is stacked on and comes in contact with an unexposed portion that has been optically determined and will form a flow channel. For this reason, there has been a concern that polymerization initiating species which have been produced from a photopolymerization initiator contained in the stacked photoresist diffuse into the unexposed portion in the above described lower layer, which unexposed portion will be a flow channel, and result in causing a polymerization reaction. In other words, there has been a concern that an actual height of the flow channel results in being lower than the desired height. Specifically, there has been a concern that, as is shown in FIG. 4, the actual height of the flow channel is made lower than the desired height of the flow channel because the substance which causes the polymerization of the above described unexposed portion in the lower layer invades into the unexposed portion to form a cured portion 15.